jfs_mkfs - create a JFS formatted partition
jfs_mkfs [options] device [ blocks ]
jfs_mkfs is used to create (format) a JFS partition. jfs_mkfs must be
run as root.
device is the special file name corresponding to the actual device
(e.g. /dev/hdb1) on which a JFS file system and/or JFS journal will be
created. blocks is the number of blocks to be used for the file
system. If omitted, jfs_mkfs automatically figures the file system
The default block size is 4096.
jfs_mkfs will destroy all data on the specified device!
-c Check the device for bad blocks before building the file system.
Create the external JFS journal on journal_device , create the
JFS file system on device , and attach the external journal to
the file system.
Create the JFS journal on its own device or attach an external
JFS journal to the JFS file system using options specified on
the command-line. The following journal options are supported:
Create an external JFS journal on the given device.
Attach an existing external JFS journal located on
external-journal to the JFS file system that will be
created on device. The external journal must
already have been created using the command
jfs_mkfs -J journal_dev external-journal
Attach the external journal to the file system being
created by using the command
jfs_mkfs -J device=external-journal device
Instead of specifying a device name directly,
external-journal can also be specified by either
LABEL=label or UUID=UUID to locate the external
journal by either the volume label or UUID stored in
the JFS external log superblock at the start of the
journal. Use jfs_tune(8) to display a journal
device's volume label and UUID. (See the -l, -L,
and -U options of jfs_tune(8).)
Only one of the journal_dev or device= options can be given per
Set the volume label for the newly formatted device.
If -L volume_label is used along with -J journal_device, the
volume label of the specified external journal device will be
set to volume_label. Otherwise, the volume label of the JFS
file system will be set to volume_label.
-O Provide case-insensitive support for compatibility with OS/2.
-q Quiet execution - do not ask for confirmation before creating
the file system.
Set the log size (in megabytes) of the inline log. If the -s
option is not used, the default log size is 0.4% of the
-V Print version information and exit (regardless of any other
Format 3rd partition on 2nd hard disk with the volume label "JFS_hdb3":
jfs_mkfs -L JFS_hdb3 /dev/hdb3
Format 5th partition on 1st hard disk, verifying each block created:
jfs_mkfs -c /dev/hda5
Format 3rd partition on 2nd hard disk as external journal, format 4th
partition on 1st hard disk as JFS file system, and attach the external
journal to the file system:
jfs_mkfs -j /dev/hdb3 /dev/hda4
If you find a bug in JFS or jfs_mkfs, please report it via the bug
tracking system ("Report Bugs" section) of the JFS project web site:
Please send as much pertinent information as possible including any
error messages resulting from running jfs_mkfs.
mkfs(8), jfs_fsck(8), jfs_fscklog(8), jfs_tune(8), jfs_logdump(8),
Barry Arndt (email@example.com)
William Braswell, Jr.
jfs_mkfs is maintained by IBM.
See the JFS project web site for more details:
March 9, 2005 jfs_mkfs(8)